1. Field of the Invention
This invention relates to x-ray phosphors. More particularly it relates to europium-activated alkaline earth fluorohalide phosphors.
2. Prior Art
Europium-activated alkaline earth fluorohalide phosphors are known and are disclosed in the Netherlands Pat. No. 7,206,945 and in an article published by Sommerdijk, Verstegen, and Bril in J. Lumin. 8 pp 502-506, 1974. These references disclose materials of the formula MeFX wherein Me is strontium or barium and X is chlorine or bromine. These are disclosed to be activated by divalent europium.
In Canadian Pat. No. 842,704 a process is also disclosed for preparing europium-activated barium fluoride. In that patent the europium is reduced to the divalent form.
It is believed, therefore, that a europium-activated alkaline earth fluorochloride x-ray phosphor having an improved brightness would be an advancement in the art.